Audiometer switch



0ct. 4, 1955 R. E. ALLlsoN AUDIOMETER SWITCH 2 Sheets-Sheet l Filed April 9, 1953 AAA INVENToR.

BY M/ 0ct. 4, 1955 R. E. ALLlsoN 2,719,897

AUDIOMETER SWITCH 2 Sheets-Sheet 2 Filed April 9, 1953 United States Patent O AUDIOMETER SWITCH Ralph E. Allison, Whittier, Calif., assignor to Patent Management, Incorporated, Minneapolis, Minn., a corporation of Minnesota Application April 9, 1953, Serial No. 347,791 2 Claims. (Cl. 200-153) This invention relates to improvements in audiometers and particularly to switches used in the electrical circuits thereof which control the tone generated thereby.

Early audiometers were so constructed that during their use the tone generated by the audiometer was normally left on, and at the will of the operator or tester of the past it was turned off or discontinued by pressing a control switch. Subsequently, it was found desirable to be able to optionally leave the tone on and interrupted by the operator or tester or, in the alternative, to leave the tone olf and to optionally turn it on momentarily at the will of the operator.

To meet this requirement, audiometers have recently been constructed wherein two switches were incorporated in the circuit. One of these switches has heretofore consisted of a three blade, single pole, double throw switch, and an auxiliary switch of the double pole, double throw type, in order to make both types of operation or testing available. When the double pole, double throw switch was in one position, then tone was normally on and a push button switch was effected to turn it off momentarily. When the push button switch was released, the tone continued. When the double pole, double throw switch was thrown in opposite position, the tone was normally off and the push button switch caused the tone to be momentarily turned on whenever it was depressed. This combination of two switches ordinarily required the use of nine soldered connections.

An object of the present invention is to provide an irnproved switch that may be easily incorporated in an audiometer circuit, and which is so designed that the control bar or handle thereof will be urged into either of two positions from which it may be momentarily displaced and to which it will automatically return when released. In one of these positions contacts will be made, such as to cause the tone of the audiometer to be generated, and when the handle is momentarily displaced therefrom the tone will be interrupted. When the handle of the switch is turned into the other position, the situation will be reversed, that is, contacts will be made such that the tone is normally off but when the handle is displaced from this position the tone will be temporarily generated and discontinued automatically when the handle is released.

In this manner, the operator or tester can secure either type of operation that he desires. If he wants the tone continuously generated, he may turn the handle into one normal position and interrupt the tone by merely displacing the handle from this position. On the other hand, if the operator Wants the tone normally off, he may turn the same handle to the other normal position and may momentarily generate the tone by displacing the handle momentarily from this position.

By means of the improved switch, it is possible to eliminate from the audiometer circuit six soldered connections, one handle or knob, and one entire switch.

With the foregoing and other objects in View, which will be made manifest in the following detailed description and specifically pointed out in the appended claims,

2,719,897 Patented Oct. 4, 1955 ICC reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a perspective view of an audiometer embodying the present invention;

Fig. 2 is a partial View in section showing the switch embodying the present invention in side elevation;

Fig. 3 is a rear view in elevation of the switch, illustrating the handle of the switch in one of its two normal positions;

Fig. 4 is a View similar to Fig. 3, but illustrating the handle as having been temporarily displaced from the normal position shown in Fig. 3;

Fig. 5 is a View similar to Fig. 3, but illustrating the handle in its other normal position;

Fig. 6 is a view similar to Fig. 5, but illustrating the handle as having been temporarily displaced from the normal position shown in Fig. 5 and Fig. 7 is a wiring diagram of the audiometer illustrating the location therein where the switch embodying the present invention may be advantageously located.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the wiring diagram shown on Fig. 7 is, in the main, a conventional wiring diagram of an audiometer wherein a source of electrical potential is supplied through leads 10 and 11. 1.2 indicates a voltage regulator, and 13 and 14 are two resistances between which the switch 15 constituting the present invention is located. The condenser 16 functions in conjunction with either resistance 13 or 14.

17 indicates generally an oscillator circuit connected to the switch 1S, and this oscillator circuit is, in turn, connected to an attenuator, generally indicated at 17, having various taps which are calibrated in frequencies supplied to an earphone, or speaker, 18. When the switch 15 is connected to the resistance 13 current is supplied to the oscillator circuit through the attenuator and causes a tone of a frequency determined by the attenuator to be generated by the earphone, or speaker, 18. The resistance 13 together with the condenser 16 governs the build up. Conversely, when the switch 15 is connected to the resistance 14, the resistance 14 together with the condenser governs the decay in the circuit. In this manner, clicks are eliminated as the tone generated at 18 is turned on or turned oit.

The switch which I employ at 15 in the audiometer circuit consists of a rocker shaft 20 that may be rotatably mounted in any suitable bearing 21 that may be mounted on the panel board 22 of the audiometer. This rocker shaft is equipped at its forward end with a handle 23 which extends radially from the axis of the rocker shaft so that it may also function as an indicator of the position of the rocker shaft, and as a means by which the rocker shaft may be manipulated. Behind the panel board 22 the rocker shaft 20 is equipped with a cam 24 having two spaced parallel ilats 25 and 26. Between these fiats the cam 24 presents a circular configuration.

A cantilever spring 27 is mounted on the panel board and is biased against the periphery of the cam 24. This spring serves to urge the rocker shaft into one of the two normal positions. One such position is indicated in Fig. 3, wherein the handle 23 is extending horizontally toward the right. In this position the spring 27 is resting flatly against the flat 26. The other normal position assumed by the rocker shaft is as depicted in Fig. 5, wherein the rocker shaft has been forcibly rotated by the handle 23 180 from the position shown in Fig. 3 and the handle consequently extends toward the left. In this normal position the spring 27 is resting flatly against the flat 25. If the handle, when in the position shown in Fig. 3, is depressed into the position shown in Fig. 4, the hat 26 is displaced with respect to the spring 27. However, whenever the handle 23 is released while in the position shown in Fig. 4 the spring 27 is effective to automatically return the rocker shaft to the normal position shown in Fig. 3. Similarly, as the rocker shaft is in the normal position shown in Fig. 5 and is displaced into the position shown in Fig. 6 and the handle is then released, the spring 27 will automatically return the rocker shaft to the position shown in Fig. 5.

A radial pin 2S is provided on the cam 24 and is engageable with either of two stationary pins 29 and 30 on the panel 22 or on the bracket 31 that supports the contacts and contactor of the switch. Thus, when the rocker shaft is in the position shown in Fig. 5 and the handle 23 is displaced into the position shown in Fig. 6, pins 28 and 29 engage to limit the extent to which such displacement may take place. Similarly, if the handle is in the position shown in Fig. 3 and is displaced into the position shown in Fig. 4, pins 29 and 30 engage to limit the displacing movement.

Beyond the cam 24 the rocker shaft has a second cam 32. This cam has two flats 33 and 34. The fiat 33 is arranged parallel to the at 25 but the iiat 34. is arranged at an angle to the iiat 26. A resilient contactor 35 is mounted on the bracket 31 and is arranged in the path of the cam 32. On opposite sides of the contactor there are two resilient contacts 36 and 37 engageable thereby. These contacts are connected to the resistances 13 and 14, respectively, and the contactor 35 constitutes the mechanism embodiment of the switch indicated at 15 on the wiring diagram shown in Fig. 7.

In the position shown in Fig. 3 the high point on the cam 32 at the bottom of the at 34 engages the contactor 35, holding it in contact with the contact 36 and out of the engagement with the contact 37. Consequently, in this position electric current is being consistently supplied to the oscillator through the attenuator and to the earphone, or speaker, 18.

If the handle 23 is depressed from a position shown in Fig. 3 to the position shown in Fig. 4, the iiat 34 is caused to assume a position parallel to the length of the contactor 3S. This allows the contactor 35 to disengage coni J tact 36 and to engage contact 37. The disengagement of Contact 36 breaks the supply of current to the oscillator and the engagement of the contactor 35 with the contact 37 connects the resistance 14 with the condenser 16 so as to provide the proper decay and avoid the objectionable click. In this manner, the depressing of the handle 23 from the position shown in Fig. 3 to the position shown in Fig. 4 causes the tone generated by the audiometer to be interrupted so long as the handle 23 is held depressed. Whenever the handle is released, the spring 27 is effective to return it to the position shown in Fig. 3, wherein conditions for the generation of a continuous tone are resumed.

Should the operator, or tester, prefer the reverse set of conditions, namely that the tone shall be normally oif and only momentarily turned on when the handle 23 is depressed, all that is required is to turn the handle 23 to 180 to the position shown in Fig. 5. In this position the fiat 33 on the cam 32 is disposed in opposition to the contactor, allowing the contactor 35 to engage the contact 37 and to disengage the contact 36. When electrical connections are thus made, the contactor and contacts are in the same position as shown in Fig. 4 so that no tone is being generated. However, when the handle 23 is depressed into the position shown in Fig. 6, the contactor is engaged by the high point on the cam 32 and moved out of engagement with the contact 37 and into engagement with the contact 36. This causes tone to be generated at the earphone, or speaker, 18 so long as the handle is depressed. Whenever the handle is released from the position shown in Fig. 6, the spring 27 is automatically eiective to return the rocker shaft to the position shown in Fig. 5, discontinuing any further generation of tone.

From the above described construction it will be appreciated that with the improved switch the operator, or

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tester, using the audiometer can secure whatever condition of operation or testing that he desires. If he wants the tone to be normally on, he merely shifts the handle 23 to the position shown in Fig- 3 and depresses the handle to the position shown in Fig. 4 to secure momentary periods of interruption. On the other hand, if he wishes the tone to be normally oif, he merely rotates the handle 23 to 180 into the position shown in Fig. 5 and can secure momentary generations of tone by depressing the handle into the position shown in Fig. 6. In this manner a single switch having a single handle may be utilized to secure all desirable conditions of testing. Furthermore, the number 0f soldered connections required in the circuit can be materially reduced, it being merely necessary to make appropriate connections between the oscillator circuit and the contactor 35, the resistance 13 with the contact 36, and the resistance 14 with the Contact 37.

Some audiometer circuits are so arranged that a single Contact and an associated contactor controls the sound generated by the speaker 18. In such audiometer circuits one of the contacts 36 or 37 may be dispensed with and the improved switch may still be advantageously used. For example, if the contact 36 is dispensed with and the remaining structure remains the same the handle 23, when in the position shown in Fig. 3, will hold the contactor 35 out of engagement with the Contact 37. On swinging the handle into the position shown in Fig. 4, the contactor 35' is allowed to engage the Contact 37, causing a tone to be generated. On release of the handle 23 it returns to the position shown in Fig. 3 automatically causing the cam 32 to disengage the contactor from the contact. In the alternative, if the handle 23 is thrown to the other extreme position as depicted in Fig. 5, the cam allows the contactor 3S to normally engage the contact 37 and cause the tone to be continuously generated. On depressing the handle into the position shown in Fig. 6, the contactor will be caused to momentarily disengage the contact 37 to interrupt the tone which is resumed whenever the handle is ,released so that it may return to the position shown in Fig. 5. In this manner, the switch may be advantageously used in conjunction with such audiometer circuits to conveniently enable either method of operation, that is, a tone-off condition wherein the tone is momentarily brought on or in a normal tone-on condition that is momentarily interrupted.

I claim:

1. A switch for audiometers and the like comprising a handled rocker shaft, a cam on the rocker shaft presenting two iiats, a spring engageable with the cam and when in engagement with the flats thereof urging the rocker shaft into either of two normal positions from which it may be rotated from one normal position to the other, means limiting rotation of the rocker shaft beyond either of said normal positions, a contactor, iirst and second contacts engageable by the contactor, the contactor being biased to engage the first contact and disengage the second, and a second cam on the rocker shaft engageable with the contactor, said second cam having a fiat parallel to one of the iiats on the first cam and another at angularly related to the other flat on the iirst cam whereby when the rocker shaft is in one of its normal positions the contactor will engage the first contact and disengage the second and when the rocker shaft is rotated beyond said normal position the contactor will disengage the iirst contact and engage the second and when the rocker shaft is in the other of its normal positions the contactor will engage the sec ond contact and disengage the iirst and when the rocker shaft is rotated beyond said other of said normal positions the contactor will engage the first contact and disengage the second.

2. A switch for audiometers and the like comprising a handled rocker shaft, a first cam thereon presenting two flats, a spring biased against said cam urging the rocker shaft into either of two normal positions, a contactor adjacent the rocker shaft, first and second contacts engageable by the contactor, a second cam on the rocker shaft engageable with the contactor, said second cam having two flats one of which is parallel to one of the flats on the rst cam and the other of which is angularly related to the other of the flats on the iirst cam whereby when the rocker shaft is in one normal position, the contactor will be engaging the first contact and disengaging the second and will be caused to disengage the first contact and engage the second when the rocker shaft is rotated slightly from said normal position and when the rocker shaft is in the other normal position, the contactor will be disengaging the first contact and engaging the second and will be caused to engage the first contact and disengage the second when the rocker shaft is rotated slightly from the last- 5 mentioned normal position,

References Cited in the le of this patent UNITED STATES PATENTS 1,830,138 Smith et al. Nov. 3, 1931 l0 2,280,438 Matthews Apr. 21, 1942 2,611,835 Mossman Sept. 23, 1952 

